Pneumatically driven surgical instrument



Oct. 14, 1969 R. M. HALL 3,472,323

PNEUMATICALLY DRIVEN SURGICAL INSTRUMENT Filed Oct. 24, 1967 sSheets-Sheet 1 1!; VENT-OR Passer M HALL CAEOTHE$ (neon/5e:

#15 A TTOEAI'YS Oct. 14, 1969 HALL PNEUMATICALLY DRIVEN SURGICALINSTRUMENT Filed Oct. 24, 1967 3 Sheets-Sheet Reefer/ 1 HAM m"CAROTHER6C40THE5 R. M. HALL I PNEUMATICALLYDRIVEN SURGICAL INSTRUMENTFiled Oct. 24, 1967 Oct. 14, 1969 5 Sheets-Sheet T 05527 /ZZZ BY (A/Porue/25 (A/90mm H/s Arra RAIL Y5 United States Patent 3,472,323PNEUMATICALLY DRIVEN SURGICAL INSTRUMENT Robert M. Hall, 1253 CoastVillage Road, Santa Barbara, Calif. 93103 Filed Oct. 24, 1967, Ser. No.677,664 Int. Cl. E21b 1/02; F15b 13/04; FOld 15/06 US. Cl. 173-463 7Claims ABSTRACT OF THE DISCLOSURE A pneumatically driven surgicalinstrument having a rotor motor within a housing shell with valve meansto selectively control the pneumatic supply to the rotor motor. Anoutput spindle is supported on the forward end of the housing shell androtatably connected to the rotor motor. Adapter means are provided onthe forward end of the housing shell to various types of auxiliarysurgical appliances of dilferent manufacture and torque requirements.Means are provided in the surgical instrument to selectively vary thedeveloped torque and speed of the rotor motor to meet those torquerequirements in the form of (a) a specially constructed valve body inthe rotor motor valve means and (b) means to vary the actual location ofentry of the pneumatic supply input to the rotor motor.

BACKGROUND OF THE INVENTION Field of invention This invention pertainsto surgical instrument devices designed for use in operative surgerytogether with auxiliary devices used in operations.

Description of prior art The use of pneumatically operated surgicalinstruments in surgery was long ago conceived with practical fluidoperated surgical devices beginning to appear in the 1940s. Since 1957,there has been unprecedented increase in the design and practicalutilization of pneumatically operated instruments exclusively forsurgical application. These new high speed operated instruments have nooverheat problems and eliminate possible explosion problems in theoperating room now possibly present with electrical operated surgicaldevices. Such pneumatically operated instruments also provide precisionbone cutting and shaping during surgery in a fraction of the time ittakes in using hand tools, such as hand drills and saws, which arerapidly being replaced by the high speed pneumatically operated surgicalinstrument.

Although the pneumatically operated surgical instruments are a blessingto surgery, there has erupted a whole new field of problems accompanyingthe ultimate practical use of these instruments in the surgical field.This invention is directed to the solving of one of those problems.

Automatically driven surgical instruments of the past which have beenelectrically driven bring a potential danger to the operating room sincethere is a risk of explosion due to the highly volatile and inflammablenature of anesthetic agents. At the same time, such electrical driveninstruments were connected to a flexible drive cable controlled by afoot switch, the former making it cumbersome to properly operate andsurgically apply the instruments and the latter being a potentialobstruction for tripping over or accidentally stepping upon by personspresent in the operating room. These potential hazards are eliminated bythe pneumatically driven surgical instrument comprising this invention.

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SUMMARY OF INVENTION The present invention is directed to apneumatically operated surgical instrument similar to the type now knownin the pneumatic surgical art but particularly directed to apneumtically operated surgical instrument capable of being utilized withvarious types of surgical appliances, such as surgical saws, drills, animpactor and extractor, and dermatomes.

Various types of pneumatically operated surgical instruments have beendeveloped with adequate torque characteristics depending upon theparticular application to which the instrument is to be ultimatelyapplied. Thus, in the case of an orthopedic screw driver the torquerequirements are set within the instrument by designing the desiredtorque rating of the rotor motor. On the other hand, it is necessary toprovide a different value of torque rating for the surgical oscillatingsaw since the application of this instrument is quite dilferent than theorthopedic screw driver.

The present invention provides an instrument wherein the value of torquerating developed by the rotor motor may be selectively varied to permitthe use of a single surgical instrument of the pneumatic type for manydifferent types of surgical appliances requiring different surgicalapplications.

The surgical instrument of the present invention has a unique qualitynot known in the prior art, in being versatile in a multitude ofsurgical applications. This versa tility not only rests in the abilityto selectively vary the applied torque of the rotor motor but also restsin connection with the adaptor means provided at the forward end of thesurgical instrument housing shell. The adaptor means of the presentinvention permits; the utilization of not only newly developed surgicalappliances that may be driven by the present pneumatic surgicalhandpiece or instrument but also by those appliances previously found inthe art which are adapted to be driven by the conventional electricmotor drive adapted for surgical use.

Another feature of the present invention resides in the valve means usedfor supplying pneumatic pressure to the rotor motor. The valve means ofthe present invention is provided to give uniform control in the desiredamount of pneumatic pressure to be applied to the pneumatically operatedrotor motor. This is brought about by the particular design of the valvebody of the valve means Wherein it takes the form of a parabolic sector.

The pneumatically driven surgical instrument comprising this inventioncomprises an elongated housing shell within which is mounted a rotormotor comprising a rotor eccentrically mounted Within a cylindricalmotor housing. The eccentricity of the rotor relative to its rotorhousing forms a crescent-shaped expansion chamber. Rotation of the rotorpermits radial movement of the rotor blades from within the rotor, whenpassing through the crescentshaped expansion chamber, and, conversely,their withdrawal within the rotor upon their passing a point wherein therotor surfaces comprising the expansion chamber converge to a pointsubstantially tangent relative to the inner annular surface of the rotorhousing. Valve means, as above mentioned, is provided in the housingshell to selectively control the pneumatic supply to the rotor motor.The speed and developed torque of the rotor motor may be varied byoperation of the valve means.

A second valve means may be provided in connection with the rotor motorin order to vary the developed torque of the rotor. This second valvemeans may take the form of a series of inlet ports arcuately positionedalong the inner surface of the cylindrical rotor housing commencing fromthe point of divergent of the side walls of the crescent-shapedexpansion chamber. One may select the de sired inlet port in order tovary the actual position or 10- cation of entry of the pneumaticpressure supply into the rotor expansion chamber. The further the supplyof inlet pneumatic pressure is provided away from the point ofdivergence of the expansion chamber sidewalls, the greater the rotaryspeed, but with a corresponding reduction in the developed torque.Conversely, the closer the inlet port of the pneumatic supply to thepoint of divergence of the crescent-shaped expansion chamber side walls,the greater the developed torque of the rotor motor with a correspondingdecrease in speed. Thus, the present invention provides means to readilyselectively adjust the developed torque rating of the rotor motor to adesired value in order to meet and satisfy the torque requirements of anumber of surgical appliances that may be attached on the forward end ofthe housing shell through the use of adaptor means provided thereon.

The adaptor means may take the form of a coaxially aligned member, beingcoaxial relative to the output drive spindle of the rotor motor. Theadaptor means is provided with a series of detent means thereon toreceive and removably secure the above mentioned appliances foroperation through the output drive spindle. The detent means may takethe form of an appliance mounting shoulder formed on the outer forwardsurface of the housing shell or may comprise a series of ball detentdimples or recesses positioned circumferentially around the outersurface of the adaptor means to receive and detachably retain anauxiliary surgical appliance to be driven by the output drive spindle.

Thus, the purpose of the present invention is the provision of apneumatically driven surgical instrument having universatility and beingcapable of being used with a number of many different types of auxiliarysurgical appliances, no matter their particular design or manufacture incombination with the capability of providing a means to selectively varythe torque of the motor drive in order to meet the torque requirementsof any of the auxiliary surgical appliances that may be used inconnection with the instrument.

Other objects and advantages appear hereinafter in the followingdescription and claims.

The accompanying drawings show for the purposes of exemplification,without limiting the invention thereto certain practical embodimentsillustrating the principles of this invention wherein:

FIG. 1 is an exploded view of the pneumatic supply and exhaust assembly,pneumatically operated rotor motor and its housing shell of the surgicalinstrument comprising this invention.

FIG. 2 is a longitudinal cross-section of the pneumatically drivensurgical instrument comprising this invention.

FIG. 3 is an exploded view of the pneumatic pressure supply and exhaustassembly.

FIG. 4 is a detail cross-section of the structure in the supply andexhaust assembly to operate the variable pneumatic input to the rotormotor.

FIG. 5 is a perspective view of an end of the rotor motor housing with across-sectional detail of the pneumatic pressure input ports.

FIG. 6 is a cross-sectional view of the detailed section taken along theline 5-5 of FIG. 4.

As shown in FIGS. 1 and 2 the pneumatically driven surgical instrument 1is provided with a housing shell 2 to support the rotor motor 3, thepneumatic pressure supply and exhaust assembly 4, the head 5 housing thevalve means 6 and the adaptor means 7 at the forward end of the housingshell 2.

The input pneumatic supply line 8 has the coupling 10 which isthreadably secured to the rearward end of the head 5 to permit thepassage of the pneumatic supply into the head chamber 9, thence throughthe diagonal chamber 11 into the enlarged chamber 12 of the valvechamber 13. A transverse entry 14 is provided in the head 5 to permitthe insertion of the oiler 15 to introduce lubrication into thepneumatic supply to provide continual lubrication to the rotor motor 3.

The valve means 6 comprises the valve body 16, valve stem 17 and valvespring 18. The valve body 16 is housed within the valve chamber 13 whichconsists of the enlarged chamber 12, previously mentioned, and thesmaller cylindrical valve chamber 20. Due to the differences in the sizeof the enlarged valve chamber 12 and the smaller valve chamber 20 thereis provided a shoulder 21 therebetween to form a valve seat.

The valve body 16 in reality consists of two sections. As will be notedin FIG. 2, the upper section 19 of the valve body 16 is provided with anannular groove 22 which receives the elastomer O-ring 23 which rests inposition, biased by the valve spring 18 on the valve seat 21 and thusforms a valve seating surface for the valve body 16. The lower or otherbody section of the valve body 16 consists of a parabolic sector section24 which is receivable within the bounds of the smaller valve chamber20. The particular form of this valve section is important in that itprovides proportional and uniform control of the desired quantity ofpneumatic pressure supply to be provided to the rotor motor 3.

The spring 18 maintains the valve body 16 in its normal seated positionand is biased against the stud 25 of the upper valve body section 19with the other end is housed within the aperture 26 provided in thevalve chamber seal nut 27.

The valve stem 17 extends outwardly through the head 5 through the gland28 and its captive O-ring 30 where the outer end of the stern engagesthe control lever 31 of the pneumatically driven surgical instrument 1.The control lever 31 is pivotally secured to the head 5 of the surgicalinstrument 1 at 32. An aperture 33 may be provided in the head 5 inorder to permit the insertion of the spring member 34 to bias thecontrol lever 31 against the end of valve stem 17 and toward the body orhousing shell 2.

The parabolic shape of the valve section 24 is an important feature ofthe present invention. Most valves of this type are circular ortrapezoidal in cross-section and, as such, do not permit the direct andeven proportional control of the pneumatic pressure supply relative toincremental valve movement. The application of a valve body employing aparabolic sector in the valve chamber opening permits evenly distributedand applied pneumatic supply pressure with corresponding incrementalmovement of the valve 16 through the control lever 31.

Upon operation of the valve means 6, the pneumatic pressure supply ispermitted to pass through the chamber 13 into the head passage 35wherein the supply is thence directed to the pneumatic pressure suplyand exhaust assembly 4.

As shown in FIG. 2, the pneumatic pressure supply enters the distributor36 of the pressure supply and exhaust assembly 4. As shown in FIG. 3 aswell as FIG. 2, the supply is permitted to pass through the centralopening 37, thence diagonally through the transverse opening 38 to theinlet supply vein or corridor 40, the latter of which, as can be seenfrom FIG. 3, is made up of a number of openings in the various partscomprising the assembly 4, each part being aligned relative to oneanother by the alignment pin 57 when assembly 4 is properly assembled.

A screen 9 may be provided in the passage or opening 37 to filter theincoming pressure supply and prevent the passage of any contaminatingdirt or foreign matter.

As shown in FIG. 3 the pneumatic pressure supply and exhaust assembly 4comprises the distributor 36, the cover plate 41, the bearing plate 42,the vent plate 43 and the end plate 44, the latter of which forms animportant structure comprising an important feature of this in-.vention.

The cover plate 41 of the assembly 4 functions as a separator for thedistrbuitor 36 and the bearing plate 42. As shown in FIG. 2 the bearingplate 42 centrally supports the bearings 45 which bearing supports oneend of the axle 46 of the rotor motor 3. The axle 46 passes through acentral opening provided in the end plate 44 and the vent plate 43 andis housed in the spacer 47 which has the lip 48 abutting the inner raceof the bearing 45. The spacer 47 performs the function of a sleevebearing relative to the vent plate 43 and the end plate 44.

The rotor motor 3 consists of the rotor 50 having a series of radialslots 51 longitudinally disposed for receiving the rotor blades 52. Therotor blades 52 are generally made of a fiber type material and arepermitted to move radially relative to the central axis of rotation ofthe rotor 50 upon high rotational movement of the same. The rotor motor3 is provided with its own rotor housing 53 and as shown in FIG. 1, therotor housing 53 is positioned eccentrically relative to the centralaxis of the rotor 50. This positioning forms the crescent-shapedexpansion chamber 54 as clearly illustrated in FIG. 6. The rotor blades52 are readily permitted to extend into the chamber 54 from theirrespective blade slots 51.

The rearward end of the axle 46 is provided with the longitudinalgrooves 49 to receive the rotor keys 39 to enable the rotor 50 torotatably drive the axle 46 as well as the output spindle 63.

As can be seen in FIG. 1, the eccentricity of the housing 53 relative tothe rotor 50 is such that the rotor 50 is tangent to its housing 53 atone position which is generally in the vicinity of the alignment pinhole 55. The rotor blades 52 of the rotor 50 when passing this positionrelative to the rotor housing 53 are maintained by the rotor housingwall within their radial slots 51.

A series of alignment pin openings 56 are provided in the parts makingup the supply and exhaust assembly 4 and form the alignment pin hole ofthe assembly 4 as assembled. Thus, the alignment pin 57 properlypositions each of the various parts comprising the assembly 4 andassemblies them in proper relationship relative to the cylindrical rotorhousing 53, the pin 57 extending from the opening 56 of the assembly 4into the alignment hole 55 in the housing 53. Also, the sides of thehousing 53 and the assembly 4, as shown in FIG. 1, areflattened at 130to fix their position within the shell housing 2.

The other end of the rotor axle 46 is supported for rotational movementin the bearing 58 supported in the bearing plate 60. The end plate 61provides the forward end cover for the rotor motor 3 and alsopneumatically seals that end of expansion chamber 54. With thecomponents of FIG. 1 assembled, the expansion chamber 54 is relativelydefined by the eccentric positioning of the housing 53 relative to therotor 50 together with the rearward and forward end plates 44 and 61. Aspacer 62 is provided for rotatably supporting the axle 46 relative tothe inner race of the bearing 58 and, as such, necessarily acts as asleeve bearing for rotational movement of the axle 46 relative to theend plate 61. End seals 132 are provided at the ends of the rotor 50 mprovide pneumatic sealing for chamber 54 where axle 46 enters into thechamber area. i

The output spindle 63 has a shoulder abutment 59 and a bearing lock nut64 to secure the position of the inner bearing race of the spindlebearing 65. The spindle hearing 65 rotatably supports the output spindle63 for driven movement by the rotor motor 3. An annular spacer 66 isprovided between the outer races of the bearings 65 and 58 in order tomaintain the same in their proper spaced relation as well as theirproper position within the forward end of the housing shell 2.

The adaptor means 7 is threadably secured to the forward end of thehousing shell 2 at 69 and is coaxially aligned relative to the outputspindle 63, the latter passing through the central bore 67 of theadaptor means 7. The adaptor means 7 is provided with a series of balldetent dimples or recesses 68 which are positioned annularly around theouter surface of the same. A multiple number of detent dimples in theadaptor means 7 permits the selection of a number of possible positionsfor a mounting attachment or appliance, thus allowing for the desiredlocation of the control lever 31 relative to the auxiliary appliance tobe attached to the adaptor means to be used in a surgical procedure. Theadaptor means 7 provides a means for readily attaching an auxiliarysurgical appliance to the instrument 1 by visually aligning the outputspindle 63 with alignment key 70 when inserting the spindle 63 into theappliance to assemble the same on the instrument 1. The appliance willbe mounted against the mounting surface 79 of the adaptor means 7. Atthis time, the appliance may "be readily turned about on the adaptormeans 7 and the surgeon may select the most comfortable or convenientlever location for the particular attached auxiliary appliance relativeto the surgical instrument 1. This location depends upon the intendedapplication of the appliance being used and the employment of thecontrol lever 31 relative to the operation of that attached surgicalappliance. For example, in the use of an attached reciprocal impactor,extractor appliance, the control lever 31 is preferably positionedbeneath the instrument 1 as shown in FIG. 2. On the other hand, whenusing an attached oscillating bone saw, it is preferable to position thecontrol lever 31 above the instrument, that is, 180'from the positionshown in FIG. 2.

When an auxiliary appliance is assembled to the handpiece or instrument1, a spring-loaded ball in the attaching collet of the appliance (notshown) will drop into any selected one of the selected dimples orrecesses 68 depending upon the desired lever location. The attachedappliance is securely attached for surgical use and when such use hasbeen made, the appliance may be readily withdrawn from the adaptor means7.

Reference is again made to the support bearing ring 60 together with theend plate 61 which are provided with an opening in their upper portiongenerally indicated at 73 in FIG. 2 for insertion of the alignment pin74 to align and maintain these parts in their proper position relativeto the rotor housing 53, the latter of which is provided with thealignment hole 75 receiving the alignment pin 74.

Referring to the end plate 44 as shown in FIGS. 2 and 3 and 4, the endplate 44 comprises a central annular support member 76 and acontrollable valve port ring 78 supported on the sleeve ring bearing 77,made of Teflon or other suitable material and mounted on the supportmember 76. The valve port ring 78 is permitted to rotate on the sleevebearing 77. The valve port ring 78 is provided with a cut-out section 89in its upper portion to permit the passage of the alignment pin 57. Thealignment pin 57 also acts as a stop for limiting the extent of annularrotational movement of the valve port ring 78.

The control arm 81 is threadably secured into the valve port ring 78and, as shown in FIG. 1 extends outside the surgical instrument 1through the slot 82 of the housing shell 2.

The valve port ring 78 provides a portion of the pneumatic supply inletvein 40 as shown in the detail of FIG. 4. The end plate 44 is providedwith the spring biased pilots 82 and 83 housed within that portion ofthe inlet vein 40 found in the end plate 44. Each of the pilots 82 and83 are provided with a head section 84 which has a shoulder 85 againstwhich the spring 86 is forcibly applied to outwardly bias the pilots 82and 83. The other end of the springs 86 rest against the annularshoulder member 87. Thus the pilots 82 and 83 are always urged outwardlyfrom within the inlet vein 40 found in the end plate 44 in order thatthe nose 88 of the pilots 82 and 83 will recessively cooperate with portcountersinks 90 located in the end of the rotor housing 53, as shown inFIG. 1 as well as the port countersinks 91 found in the vent plate 43 asshown in FIG. 3. The pilots 82 and 83 may be constructed of any suitablematerial, one such material being Teflon.

As shown in detail in FIGS. 5 and 6, the rotor housing 53 of the presentinvention is provided with four separate inlet port veins indicated as92, 93, 94 and 95, each provided with a port countersink 90. Each of theveins 92, 93, 94 and 95 are provided respectively with a radiallydisposed inlet port 96, 97, 98 and 100. The vent plate 43 is alsoprovided with a series of vents 92, 93', 94 and 95 in respective alignedrelation with the veins 92, 93, 94, and 95, each vent provided with aport countersink 91.

As noted in FIG. 6, the inlet ports 96 through 100 enable one toselectively vary the exact location of the input pneumatic pressuresupply into the expansion chamber 54 and, thus, effecting a desiredrating of the developed speed and torque of the rotor 50. Thus, if theinlet port 96 is chosen as the desired entrance or location of thepneumatic supply input by rotating the valve ring 78, the developedspeed of the rotor 50 will be reduced and there will be a great amountof developed torque which can be used in matching the torquerequirements necessary for an attached auxiliary surgical appliance.Rotor motors of the type disclosed in FIGS. 1, 2 and develop rotationalspeeds from rpm. up to 20,000 rpm. and, conversely, torque ratings from3 in pounds to 90 in pounds or more.

If one chooses to direct the input supply through the inlet port 100, anincrease in the developed rotational speed of the rotor 50 will beobtained with a corresponding reduction in developed torque. Thus, itmay be desired, for example, to adjust the valve port ring '78 to theinlet port 96 wherein an attached auxiliary appliance to the surgicalinstrument 1 is to be a surgical screw driver attachment for orthopedicprocedures, in which case, a large amount of torque is necessary inorder for this appliance to perform its job adequately. On the otherhand, it may be desired to select the inlet port 100 through adjustmentvalve port ring 78 in order to develop a greater amount of output speedrather than developed torque as in the case of a surgical bone drillappliance.

The spring biased pilots 82 and 83, as shown in FIG. 4, prevent theunauthorized passage of the pneumatic supply between the adjacentsurfaces of the vent plate 43, end plate 44 and the rearward end of therotor housing 53.

From the foregoing it will be evident that the end plate 44 is animportant feature comprising the present invention and actually is avalving means used to selectively vary the location for entrance of thepneumatic supply into the expansion chamber 54 of the rotor motor 3.

In FIG. 4 it will be noted that in order to prevent the valve support 76from rotating with the valve port ring 78, the pin member 101 of theformer is provided to b received in the opening 102 of the vent plate43. It is important that the valve port support 76 does not rotaterelative to the valve plate 43 since the rotor vent lanes 103 and 104,as shown in FIG. 3, must be positioned as shown in that figure tocorrespond with the opening 105 and passage 116 provided for in the ventplate 43.

The vent lane 103 in the valve support 76 is arcuate in shape around thecentral opening of the end plate 44 and is positioned to supplypneumatic pressure to the end of the rotor 50 in the area of the base ofthe rotor slots 51. The purpose of the vent lane 103 is to permitpneumatic pressure to enter into the bottom of the rotor slots when eachsuccessive slot with its rotor 'blade enters into the area of theexpansion chamber 54 to insure positive outward radial movement of therotor blades within the rotor slots at that time. There is no tendencyfor the rotor blade, therefore, to stick within the rotor slot 51 whenthe blade should be in an extended position from the rotor 50, as shownin FIG. 2.

From FIG. 3 it will be noted that the opening 105 in the vent plate 43is aligned with the vent lane 103 of the end plate 44 and its opening134 therethrough, pneumatic pressure supply being channeled along thevein 40 will be generally directed to the ports 92', 93, 94

and with a small portion of the same supply being diverted along thetransverse channel 106 through the opening 105, the opening 134 andthence to the arcuate vent lane 103.

As can be seen in FIGS. 1, 2 and 5, the pneumatic supply within theexpansion chamber 54 is exhausted from the chamber through the lateralopening 107 in the housing 53, thence along the exhaust corridor 108through the pneumatic supply and exhaust assembly 4, thence through theopening 109 into the arcuate exhaust chamber 110 of the distributor 36.Part of the chamber 110 is in the head 5 as shown in FIG. 2, and aseries of eccentric passageways 112 are provided in the transverse wall111 of the chamber 110 for the expended gas to be exhausted and carriedaway from the surgical instrument 1 as fast as conveniently possible.For purposes of illustration, only one such passageway 112 is shownleading from the annular exhaust chamber 110 to the annular exhaustchamber 113 where the expended gas is then directed through the outercoaxial flexible tubing 114 to a remote area for diffusion into theatmosphere. In providing several passageways such as 112 in the head 5,the expended gas from the pneumatically driven motor 3 is permitted toexist from the surgical instrument 1 as efliciently as possible andprevents any possibility of any gas build-up in the encased motor 3.This reduces the possibility of gas leakage through the internal partsof the instrument 1 to an external point resulting in contamination ofthe sterile operative field of surgery.

The flexible tubing 8 and 114 together form a coaxial hose. The tubing114 is secured to the head '5 through the use of the fitting 115 and, aspreviously mentioned, the fitting or coupling 10 secures the innertubing 8 to the head 5.

The lateral opening 107 represents the main exhaust from the chamber 54.However, the rotor motor 3 must also be provided with a secondaryexhaust means in order to eliminate compression of the gases containedbehind adjacent rotor blades passing on the diverging exhaust chamberside of the rotor 50 in an area designated at 136 in FIG. 6. Also, theremust be means provided for the rotor blades to readily move inwardlyinto their respective slots without the gases present behind each of theblades resisting the inward movement of the same. The vent lane 104 isprovided to bleed off any of the gases present in the bottom of the slot51 as the blades are moved radially therein. As shown in FIG. 3, thegases present behind the rotor blades are drawn off through the ventlane 104 and the opening 135 in the end plate 44 and thence through thediagonal passage 116 in the vent plate 43 and thence discharged throughthe exhaust vent or corridor 117. The exhaust corridor 117 is alsopresent in the bearing plate 42, the cover plate 41 and the distributor36. In the distributor 36, the expended gases in the corridor 117 aredirected through the openmg 119, as shown in FIG. 1, into the arcuateexhaust chamber 110, previously mentioned.

The gases entrapped between adjacent rotor blades 52 as the same areprogressing through the diverging side illustrated at 136 of theexpansion chamber 54 are permitted to exhaust through the port 118,thence through the arcuate opening 120 in the valve port ring 78 of theend plate 44. The arcuate port 120 is part of the exhaust corrdor 117and thus the expended gases are directed along the vent 117 to thedistributor 36. The exhaust port 118, thus, represents a secondaryexhaust means present in the expansion chamber 54.

It should be noted that, although not specifically illustrated in thedrawings, the input supply lines 92, 93, 94 and 95 extend through to theother end of the rotor housing 53 and have corresponding inlet portsaligned relative to the inlet ports 96, 97, 98, 100, respectively. Thus,the pneumatic supply is provided on both sides of the expansion chamber54 for uniform operation of the rotor 50. In the same manner, an exhaustpassage 121,

as shown in FIGS. and 6, is provided in the rotor housing 53 to asecondary exhaust port aligned with and similar to port 118 at theopposite end of the housing 53 to permit uniform escape of the expendedgases from between adjacent rotor blades on the diverging side of theexhaust chamber 54. i

It is not necessary to provide vent lanes in the end plate 61 since thevent lanes 103 and 104 are suflicient to supply and remove the gaseswithin the blade slots 51 from behind each of the rotor blades 52.

From the foregoing it should be apparent that the pneumatic drivensurgical instrument of the present invention provides a unique means forvarying the developed torque rating of the rotor motor in order to meetthe various torque requirements necessary to operate efliciently varioussurgical appliances readily attachable to the forward end of theinstrument. As previously mentioned, some of the appliances now presentin the operating room of hospitals have been formerly electricallydriven and thus adapted to torque requirements developed by electricalmotors. With the ability in the present pneumatically driven surgicalinstrument to vary the torque requirements to be developed by the rotormotor 3, the present surgical instrument lends itself to universatilityin use in the surgical field, since this pneumatic instrument can beused to drive those surgical appliances previously driven by anelectrical motor.

The operation of the valve ring 78, as previously explained, permitsunique selective control of the developed torque of the rotor motor 3 inorder to match the torque requirements of an attached auxiliary surgicalappliance. Although the selective positioning of the valve ring 78 willalso change the output rotational speed inversely relative to thedeveloped torque, the valve means 6 can be used in cooperation with thevalve ring 78 to maintain the output rotational speed of the rotor motorsubstantially constant while changing the developed torque thereof, ifit is desired to maintain a constant and specific output speed for agiven surgical application. The opposite may be true wherein thedeveloped torque is to be maintained at substantially the same valuewhile changing the output rotational speed of the instrument. An exampleof the latter condition would be the insertion of bone screws in anorthopedic procedure with the aid of a screwdriver appliance attached toinstrument 1. The torque to be applied to the screw should not be over25 inch-pounds while the surgeon may desire to vary the rotational speedof the screw when driving the same into the bone.

I claim:

1. A pneumatically driven surgical instrument having an elongatedgraspable housing shell, a pneumatically driven rotor motor mountedwithin said housing shell comprising a rotor eccentrically mountedwithin a cylindrical rotor housing forming a crescent-shaped expansionchamber, valve means in said housing shell to selectively control thepneumatic supply to said rotor motor to vary the speed of said rotor,said valve means comprising an operable valve stem secured to a valvebody, a valve chamber having an enlarged chamber and a smaller chamberwith a shoulder therebetween to form a valve seat, an annular groove inone body section of said valve body to receive an elastomer O-ringhaving a valve seating surface, the other body section of said valvebody within said smaller chamber and having the form of a parabolicsector to variably and uniformly control the quantity of pneumaticpressure supply through said valve chamber to said rotor motor.

2. In a pneumatically driven surgical instrument, an elongated graspablehousing shell, a pneumatically driven rotor motor mounted within saidhousing shell, valve means in said housing shell to selectively controlthe pneumatic supply to said rotor motor to vary the speed and developedtorque of the same, an output spindle rotatably supported from theforward end of said housing shell and connected in driving relationshipto said rotor motor, means on the outer end portion of said spindle tointerengage and drive a surgical appliance, adapter means on the forwardend of said housing shell coaxially aligned relative to said outputspindle having detent means thereon to receive and removably secure saidappliance driven by said output spindle, said valve means includingmeans to vary the location of the input for the pneumatic pressuresupply applied to said rotor motor to selectively adjust the speed anddeveloped torque of said rotor motor, said rotor motor includes a rotormounted eccentrically within a cylindrical-rotor housing to form acrescent-shaped expansion chamber, said variable means comprising aseries of inlet ports arcuately positioned along the inner surface ofsaid rotor housing starting from one end of said crescent-shapedexpansion chamber, and a rotatable valve means to direct the pneumaticsupply to a selected one of said inlet ports.

3. In the pneumatically driven surgical instrument of claim 2characterized in that said detent means is an appliance mountingshoulder formed on the outer forward surface of said housing shell.

4. In the pneumatically driven surgical instrument of claim 2characterized in that said detent means comprises a series of balldetent dimples positioned circumferentially around the other surface ofsaid adaptor means to receive and detachably retain an auxiliarysurgical appliance to be driven by said output spindle.

5. A pneumatically driven surgical instrument having an elongatedgraspable housing shell, a pneumatically driven rotor motor mountedwithin said housing shell comprising a rotor eccentrically mountedwithin a cylindrical rotor housing forming a crescent-shaped expansionchamber, valve means in said housing shell to selectively control thepneumatic supply to said rotor motor to vary the speed and developedtorque of said rotor, an output spindle with adapter means mounted onthe forward end of said housing to engageably receive and driveauxiliary surgical appliances having different torque requirements, saidoutput spindle rotatably driven by said rotor motor, said valve meansincluding means to vary the location of entry of the pneumatic supplyinput to said rotor motor to selectively adjust the developed torque ofsaid rotor motor to meet the torque requirements of said appliances,said variable means comprises a series of inlet ports arcuatelypositioned along the inner surface of said rotor housing commencing fromthe end of said expansion chamber, and rotatable valve means to directthe pneumatic supply to a selected one of said inlet ports.

6. The pneumatically driven surgical instrument of claim 5 characterizedin that said rotatable valve means includes a controllable valve portring, a spring biased pilot in said port ring having a centtral openingfor passage of inlet pressure supply through said port ring, a portcountersink for each of said inlet ports, a nose on said pilotreceivable in any of said port countersinks upon rotation of said portring.

7. In a pneumatically driven surgical instrument, an elongated graspablehousing shell, a pneumatically driven rotor motor mounted within saidhousing shell, valve means in said housing shell to selectively controlthe pneumatic supply to said rotor motor to vary the speed and developedtorque of the same, an output spindle rotatably supported from theforward end of said housing shell and connected in driving relationshipto said rotor motor, means on the outer end portion of said spindle tointerengage and drive a surgical appliance, cylindrical adaptor means onthe forward end of said housing shell coaxially aligned relative to saidoutput spindle having detent means thereon to receive and removablysecure said appliance driven by said output spindle, said detent meanscomprises a series of ball detent dimples positioned circumferentiallyaround the other surface of said adaptor means to receive and detachablyretain an auxiliary surgical appliance to be driven by said outputspindle, an annular recess provided in the forward end of said housingshell around said 11 1.2 adaptor means, the bottom of which forms amounting 3,205,873 9/1965 Renshaw 91-76 X" surface to receive in securerelation said appliance and FOREIGN PATENTS removably fix said appliancein one of a selected number of set positions relative to the surgicalinstrument de- 1,174,751 3/1959 France. terminative by said ball detentdimples. 5

ERNEST R. PURSER, Primary Examiner US. Cl. X.R.

References Cited UNITED STATES PATENTS 978,086 12/1910 Weinland 91-1211,758,760 5/1930 Price et al. 173-163 10

